Why is it?

Why is it? Why is it that mass murderers kill themselves after killing all their victims? Why not before and save everyone else all the heartache. I wish I knew so I could try to figure out how to stop them first. There is a movement actually to identify kids who harm animals as potential mass murders but I am not sure that is really going to work in all cases. And given our dismal public school track record on identifying and helping bullies before they hurt others again, I doubt it will ever be corrected. Meanwhile, here is a website on bullies that may be worth the read.... http://www.bullyonline.org/